Bicycle Mechanics - Headset "play" HELP!

Im having a problem with my headset and figured you all could help me find some kind of solution. There seems to be some "play" in my headset when holding my front brake and rocking back and forth. The star nut is in correctly and the forks are cut with the right spacing. The headscrew is pretty damn tight aswell. But still, when holding the front brake and putting force on the handle bars, I see my spacers moving forward about .5mm.

Im thinking it may be the fork-- which is a cheap eighthinch cromo fork. Maybe its not fitting in the headset as snugly as its supposed to.

Ive taken everything apart and looked it all over, tightened and retightened the headset bot, all to no avail.

Also, it is noteworthy to say im using very, very soft trials bike brake pads-- they are very sticky!

Is .5mm of movement a problem? There's no movement while i'm riding... I just figured someone here may have had a similar experience. Please help!!

when you put it back together, you need to tighten the top cap before you tighten the stem to the steerer tube. that's what compresses the bearing system and eliminates the play. then, you tighten the stem to the steerertube - this holds the system together.

if you don't have enough spacers - which sometimes you can't tell immediately - then the top cap just contacts the top of the steerer tube, rather than pushing on the spacers, stem, and ultimately compressing the bearing system.

go look into those and report back.

yes absolutely, the top cap is definitely "pinching" the spacers; it is extremely tight- to a point where my front wheel will not spin or tilt to either side when lifted off the ground.

Is there a gap between the top spacer and the top of the steer tube? There needs to be...

yes about 3mm...

Moving to mechanics.

ovalized headtube?

Are the sterm clamp bolts loose before you try to adjust the headset? That's an easy thing to miss and is often the explanation for this problem.

yes they are loose.

ovalized headtube?

Im wondering if this, or an ovalized fork tube (dont know what you call it, "crown race?") could be the issue. It seems as if the play is coming from the fit not being snug enough. Im finding out that no matter how much I pinch the headset with the compression cap, there is still play.

Can you move the pressed in cups by hand?

Clamping the front brake and rocking the bike to feel for play does not work with modern integrated headsets, or any other type using angular contact cartridge bearings. As others have noted, be sure the stem is not clamped to the steerer and there is a small gap between top cap and the steerer. It the top cap touches the steerer, it's impossible to adjust the bearing play. Another possible problem is the headset top section or conical spacer touching the head tube. Most headsets have several .25mm shim washers that can be added to insure that there is a small gap between the two.

Tighten the top cap enough to create some additional drag as the fork is turned, then back off the tightness, by 1/8 turn. Then clamp the stem to the steerer and go for a test ride. If the headset is too tight, the front wheel will not readily self-center after a turn.

There shouldn't be any play of course.

If it's a cup and cone setup first check to be sure that you have the bearing cages installed the right way. On another thread one poster mentioned that he rode for a few weeks with lots of play due to the cage being in the wrong way so that the ball bearings were not contacting both races. How it felt must have been something to expeirence. A hint that this may be the case is that the rotational resistance becomes very high with just a little preload. On good bearings and where everything is assembled in the correct order there should be small gaps everywhere and ONLY the bearing balls are in contact with anything. When it's like that you should have quite a range of preload adjustment between the initial loss of play and getting to where the rotational resistance from the preload is too high for good performance. This double checking for a sudden build up of resistance applies to cartridge style headsets. As noted some require playing with a shim stack to get shields to sit close to but not touch the cup rims.